Old fashioned LCD driver

M

Michael C

Guest
I'm in need of a chip to drive a pair of 7 segment by 6 digit LCD displays.
Each display has 50 pins (1 earth, 48 segments and I think 1 NC). It seems
everything I search for is designed for dot matrix style displays with a
bazillion pixels. Would it be possible to run the 2 displays off the same
chip and somehow alternate between the 2 (switching the earth I presume) or
would I need to drive all 96 segments seperately.

Thanks,
Michael
 
"Michael C" <mike@nospam.com> wrote in message
news:4969e9c7$0$3253$afc38c87@news.optusnet.com.au...
I'm in need of a chip to drive a pair of 7 segment by 6 digit LCD
displays. Each display has 50 pins (1 earth, 48 segments and I think 1
NC). It seems everything I search for is designed for dot matrix style
displays with a bazillion pixels. Would it be possible to run the 2
displays off the same chip and somehow alternate between the 2 (switching
the earth I presume) or would I need to drive all 96 segments seperately.

Thanks,
Michael
Click to expand...
The LCD panel should also have an input for the backplane signal.
This cannot be DC or the panel will be damaged.

You will need a flip flop per segment to hold the data to the segment
inputs. The flip flop inputs can be multiplexed to save on processor
I/O ports.

Any chance you can read the display part number?
 
Michael C wrote:
I'm in need of a chip to drive a pair of 7 segment by 6 digit LCD displays.
Each display has 50 pins (1 earth, 48 segments and I think 1 NC). It seems
everything I search for is designed for dot matrix style displays with a
bazillion pixels. Would it be possible to run the 2 displays off the same
chip and somehow alternate between the 2 (switching the earth I presume) or
would I need to drive all 96 segments seperately.

Thanks,
Michael
Click to expand...

You could use two of these from Rockby:
http://www.rockby.com.au/DSheets/25933.pdf
for five odd bucks and get 80 segments.

The datasheet shows slaved examples of the IC.
 
Mark Harriss wrote:
You could use two of these from Rockby:
http://www.rockby.com.au/DSheets/25933.pdf
for five odd bucks and get 80 segments.

The datasheet shows slaved examples of the IC.
Click to expand...
Make that: Three slaved IC's for five odd bucks each
to get 120 segments.
 
On Mon, 12 Jan 2009 16:01:54 -0800 (PST), kreed
<kenreed1999@gmail.com> put finger to keyboard and composed:

On Jan 11, 10:44 pm, "Michael C" <m...@nospam.com> wrote:
I'm in need of a chip to drive a pair of 7 segment by 6 digit LCD displays.
Each display has 50 pins (1 earth, 48 segments and I think 1 NC). It seems
everything I search for is designed for dot matrix style displays with a
bazillion pixels. Would it be possible to run the 2 displays off the same
chip and somehow alternate between the 2 (switching the earth I presume) or
would I need to drive all 96 segments seperately.

Thanks,
Michael

Could also look at silicon chips "USB CLOCK" Project. This drives a
similar sort of LCD from a PIC, using a couple of IC's.

www.siliconchip.com.au
Click to expand...
http://us1.webpublications.com.au/static/images/articles/i1109/110923_5mg.jpg

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
On Jan 11, 10:44 pm, "Michael C" <m...@nospam.com> wrote:
I'm in need of a chip to drive a pair of 7 segment by 6 digit LCD displays.
Each display has 50 pins (1 earth, 48 segments and I think 1 NC). It seems
everything I search for is designed for dot matrix style displays with a
bazillion pixels. Would it be possible to run the 2 displays off the same
chip and somehow alternate between the 2 (switching the earth I presume) or
would I need to drive all 96 segments seperately.

Thanks,
Michael
Click to expand...
Could also look at silicon chips "USB CLOCK" Project. This drives a
similar sort of LCD from a PIC, using a couple of IC's.

www.siliconchip.com.au
 
"Lord Garth" <lgarth@tantalus.net> wrote in message
news:HKtal.8583$8_3.5916@flpi147.ffdc.sbc.com...
The LCD panel should also have an input for the backplane signal.
This cannot be DC or the panel will be damaged.

You will need a flip flop per segment to hold the data to the segment
inputs. The flip flop inputs can be multiplexed to save on processor
I/O ports.

Any chance you can read the display part number?
Click to expand...
I don't have the display with me but it's your standard 7 segment x 6 digits
display (I have 2 of these to drive). Much like the display in this pic
except 6 digits.

http://us1.webpublications.com.au:80/static/images/articles/i1109/110923_5mg.jpg


 
"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:af-dnZuv-t12TfbUnZ2dnUVZ8tSdnZ2d@westnet.com.au...
You could use two of these from Rockby:
http://www.rockby.com.au/DSheets/25933.pdf
for five odd bucks and get 80 segments.

The datasheet shows slaved examples of the IC.
Click to expand...
Thanks Mark, that's pretty much perfect. Input is serial, it has 2
backplanes, it's available at digikey and it's cheap. The only downside is I
can't do it all with 1 chip :) I2C would be an advantage but I've got lots
of spare pins so not really necessary.

Michael
 
"kreed" <kenreed1999@gmail.com> wrote in message
news:08158564-0d08-43f3-8199-
Could also look at silicon chips "USB CLOCK" Project. This drives a
similar sort of LCD from a PIC, using a couple of IC's.
Click to expand...
Thanks, I will have a look.

Michael
 
"Mark Harriss" <billy@blartco.co.uk> wrote in message
news:af-dnZqv-t1uTPbUnZ2dnUVZ8tSdnZ2d@westnet.com.au...
The datasheet shows slaved examples of the IC.

Make that: Three slaved IC's
Click to expand...
I should be able to get away wih 2 of the 64 segment chips as I've got 2
displays and can put 1 on each backplane.

Michael
 
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